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Global Magnetic Fields of Galaxies and Models for the Galactic Centers

星系的全球磁场和星系中心模型

基本信息

批准号：
62540186
负责人：
FUJIMOTO Mitsuaki
金额：
$ 1.41万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

项目摘要

1. Bisymmetric spiral (BSS) magnetic fields in spiral galaxies are reproduced by using turbulent diffusion and dynamo regeneration of mean fields in the galactic gaseous disk. The BSS magnetic fields progate and rotate as a wave over large area of the disk. The angular velocity of the BSS magnetic field pattern is found to be approximately equal to that of the spiral density wave, and thus the quasi-resonant magnetogravitational interaction occurs between these two waves. Generation and maintenance of the spiral density waves are controlled by the BSS magnetic fields.2. A mathematical technique is developed to follow nonlinear motions of rotating gaseous ellipsoids in external force fiels. It is widely applied to various problems such as magnetized rotating gaseous clouds in the galactic tidal force, neutron stars emitting gravitational waves etc.. In the present research program, we followed nonaxisymmetric large-amplitude oscillation of rotating interstellar gas cloud in gravitational contraction. We are now searching for a possible relation between this violent oscillation of rotating gas cloud and star formation activities.3. We have simulated gravitational interaction between stars and giant molecular clouds using the nearest neighbour approximation. Stars are randomly accelerated, but a resultant kinetic energy is used mostly to migrate systematically inward or outward on the galactic plane: Only a small portion of the energy is stored as that of the random motion on the local galactic circular motion. The random velocity of 【.Itorsim.】50 kms<@D1-1@>D1 of population I stars can be reproduced by the gravitational interaction with giant molecular clouds, but that【greater than or equal】 50 kms<@D1-1@>D1 must be due to other notyet-identified mechanisms.

1.利用星系气盘平均场的湍流扩散和发电机再生，再现了螺旋星系中的双对称螺旋(BSS)磁场。BSS磁场以波的形式在磁盘的大区域上编程和旋转。BSS磁场图样的角速度与螺旋密度波的角速度近似相等，因此两者之间发生了准共振磁引力相互作用。螺旋密度波的产生和维持由BSS磁场控制。提出了一种跟踪旋转气态椭球在外力场中的非线性运动的数学方法。它被广泛应用于各种问题，如银河系潮汐引力中的磁化旋转气体云、发射引力波的中子星等。在本研究方案中，我们跟踪了旋转星际气体云在引力收缩中的非轴对称大振幅振荡。我们现在正在寻找这种剧烈的旋转气体云振荡与恒星形成活动之间的可能联系。我们使用最近邻近似模拟了恒星和巨型分子云之间的引力相互作用。恒星被随机加速，但合成的动能主要用于在银河系平面上系统地向内或向外迁移：只有一小部分能量被存储为局部星系圆周运动的随机运动的能量。族I恒星的随机速度[Itorsim]50 kms&lt；@d1-1@&gt；d1可以通过与巨型分子云的引力相互作用来复制，但这种[大于或等于]50 kms&lt；@d1-1@d1；d1的随机速度肯定是由于其他尚未确定的机制所致。